Geothermal Ventilation Preconditioning —A Renewable Path to Efficient, Resilient Ventilation

Having resilient solutions is critical when lowering our energy demand on the grid. The GHT Geothermal Ventilation Preconditioning Unit employs the ground’s thermal stability to efficiently pre-condition outdoor air for the Brink FLAIR ERV/HRV systems - by doing so it eliminates the need for electrical pre-heating in winter (which can draw up to 1000W) and provides free pre-conditioning/dehumidification in summer. GHT can be the low-carbon way to enhance your central HRV/ERV system’s comfort, indoor air quality (IAQ), and efficiency year-round.

What makes GHT Preconditioner Unique and Ultra-Efficient?

• Enhanced comfort: Increasing supply-air temperatures in winter improves occupant comfort, while free cooling in summer reduces the need for air conditioning and dehumidification.
• Energy savings: GHT pre-conditioning reduces reliance on electric resistance preheaters in mixed, cold, and very cold climates.
• Resiliency: By reducing or eliminating the need for electric preheaters, GHT lowers power demand on the grid by 1,000W or more.
• Sustainable performance: Utilizes renewable geothermal energy, directly supporting decarbonization goals through lower energy consumption.

By integrating GHT Geothermal Ventilation Pre-conditioning units with Passive House certified Brink FLAIR ventilation systems, engineers and Passive House designers/consultants can further enhance the already high efficiency of the FLAIR units. This is achieved by leveraging the long-term stability of earth temperatures — delivering a future-proof, “passive” upgrade that supports our shared commitment to cleaner, highly efficient buildings.

How Does Geothermal Pre-Conditioning Work?

By circulating a glycol-water mixture through geothermal piping installed either beneath the slab or below the frost line around the foundation or in the field, the GHT’s highly efficient integrated pump moves the fluid through its filter and coil. In doing so, it uses the earth’s stable temperature (40–50°F) to pre-condition incoming air before it reaches the Brink unit (or any HRV/ERV). In winter, it can warm incoming air to above 32°F (0°C); in summer, it helps pre-cool and dehumidify the air.

Key Features and Benefits

• Top-tier energy efficiency: With a coefficient of performance (COP) as high as 190*, the system delivers up to 8 kW of heating or cooling with minimal energy consumption (just 0.04 kW, used by the GHT’s internal pump).
• Lowest pressure drop across coil: The heat exchanger coil fins are designed for minimal pressure drop, so air volumes are only marginally affected. The coil is available in both aluminum and copper. Copper (used in models G8000/8001) offers the highest heat transfer rates and allows for maximum air volumes to be pre-conditioned. It is also resistant to salt spray, making it ideal for coastal environments.

• Lightweight and durable design: Constructed from expanded polypropylene (EPP), the unit is lightweight, eliminates thermal bridging, and simplifies installation.
• Flexible configuration: GHT’s design allows for either left- or right-hand installation by simply changing the filter location.
• Integrated components: Each unit includes a high-efficiency circulation pump, MERV 7/8 filter, expansion tank, pressure relief valve, and ¾" geothermal PEX connections—enabling plug-and-play installation. Models with only the high-efficiency pre-conditioning coil are also available.
  *See model breakdown below.

• Installation flexibility: Geothermal field design can use either horizontal trenches or vertical boreholes. Site-specific layouts should be designed by an engineer based on local soil conditions. Contact us for guidance or technical support.

Setup

At 475 High Performance Building Supply, we love finding smart, effective ways to improve your home’s performance and indoor air quality (IAQ). By using robust, high-quality systems that include all essential components—and that integrate easily with widely available local materials (PEX tubing, couplings, electrical wiring)—we eliminate unnecessary hurdles and help ensure efficient, professional installation.

• Geothermal loop setup: Engage a local mechanical or geotechnical engineer to design the geothermal loop—determining loop length, diameter (typically 1.25"), installation depth, and glycol concentration based on your local soil and climate conditions. For horizontal loops, ensure the depth is below the frost line (typically around 2'). Refer to the GHT Installation Guide for complete specifications.
• GHT unit installation: Mount the GHT unit before the ERV/HRV unit duct that supplies outdoor air. A wall-mounting bracket is included in the box. Connect a 40 mm P-trap (preferably waterless) to the unit’s bottom condensate drain.
• Pump automation: Use the included relay to connect the Brink FLAIR Plus Module to the GHT’s pump. Then, connect a Brink outdoor temperature sensor to the Brink Plus PCB. This setup allows the ERV/HRV to activate the GHT circulation pump whenever outdoor conditions require air pre-conditioning. For more details, see the GHT Controls Setup Instructions.

Performance Specifications

The GHT Geothermal Ventilation Preconditioner comes in multiple models and sizes to suit different ventilation requirements:

How 475 High Performance Building Supply Can Help

The Brink team at 475 is happy to answer any questions you may have on the GHT system. Please email us at brink@475.supply or fill out a quote request to get started: Brink/GHT Quote Request.